The veteran broadcaster told Sky News "making natural history film is an art".
Some viewers were outraged when it emerged that a scene in Frozen Planet, showing a bear giving birth, was filmed in a zoo.
The programme makers were accused of misleading audiences into believing the scene had been captured in the wild, but later said it would have been impossible to have filmed the footage in the wild.
Sir David, who is promoting his latest Sky 3D film, The Bachelor King 3D, said the decision to film in the zoo was made for the safety of the animal and the crew.Sir David said producers aimed to be honest and truthful during filming
"If you try to film a bear in the wild, it will either kill the cub, or kill the cameraman - or the cameraman would have to kill it. It would be disastrous," he said.
More than eight million viewers tuned into the fifth episode from the £16m seven-part BBC series in November.
Sir David said it is sometimes necessary to be creative while remaining true to life.
"Sometimes you will film one animal, then take another and cut the two together," he said.
"Sometimes you film one scene this year and another scene next year.
"What you try to do is present an a film picture as you can of the polar bear's life history."
:: The Bachelor King 3D, which airs on New Year's Eve, charts the journey of a typical King Penguin from adolescent to adult.